Pull Cord Mechanism for a Window Shade

ABSTRACT

A pull cord mechanism for a window shade includes a frame ( 1 ), a shade ( 2 ), a shade driving mechanism ( 3 ), and a pull cord ( 4 ) for driving the shade driving mechanism ( 3 ). The shade driving mechanism ( 3 ) is fixed to the frame  1  and drives the shade ( 2 ) to fold and unfold. A barrel ( 5 ) is mounted to the frame ( 1 ) at a location corresponding to the pull cord ( 4 ). The barrel ( 5 ) includes a peripheral wall having a slit ( 7 ) extending in an axial direction. A sliding block ( 8 ) is slideably received in the barrel ( 5 ). A handle ( 9 ) is mounted to an outer periphery of the peripheral wall of the barrel ( 5 ). The sliding block ( 8 ) is connected to the handle ( 9 ) by a link ( 10 ) extending through the slit ( 7 ). The pull cord ( 4 ) is received in the barrel ( 5 ). The sliding block ( 8 ) is fixed to the pull cord ( 4 ) in the barrel ( 5 ).

BACKGROUND OF THE INVENTION

The present invention relates to a pull cord mechanism for a window shade.

As disclosed in U.S. Patent Publication No. 2011/0011543 A1 (China Patent Application No. 200910041286.7), the pull cords of currently available pull cord mechanisms for driving the shade driving mechanisms of window shades are exposed. Driven by the playful nature, a child often plays the pull cord as a toy. However, the pull cord is soft and has an end fixed to the window shade, such that the pull cord is liable to tangle the child by the neck and, thus, causes danger, which potential risk has not yet been effectively solved by now.

BRIEF SUMMARY OF THE INVENTION

An objective of the present invention is to provide a pull cord mechanism for a window shade capable of effectively preventing the pull cord from tangling a child.

The present invention fulfills the above objective by providing a pull cord mechanism including a frame, a shade, a shade driving mechanism, and a pull cord for driving the shade driving mechanism. The shade driving mechanism is fixed to the frame and drives the shade to fold and unfold. A barrel is mounted through a hook to the frame at a location corresponding to the pull cord. The barrel includes a peripheral wall having a slit extending in an axial direction. A sliding block is slideably received in the barrel. A handle is mounted to an outer periphery of the peripheral wall of the barrel. The sliding block is connected to the handle by a link extending through the slit. The pull cord is received in the barrel. The sliding block is fixed to the pull cord in the barrel. In operation, the handle is moved to move the sliding block upward or downward in the axial direction. Thus, the sliding block moves upward or downward in a passageway in the barrel, actuating the pull cord to move upward or downward, which, in turn, drives the shade driving mechanism to fold or unfold the shade. Since the pull cord is received in the passageway of the barrel, children are prevented from being tangled by the pull cord, assuring use safety of the shade.

To prevent the pull cord from entangling while it is being pulled, an end cap is mounted to a tail end of the barrel to effectively prevent the sliding block from moving out of the barrel.

To allow repeated smooth movement of the pull cord, the handle is a sleeve including a hole having a shape of cross sections corresponding to that of the cross sections of the barrel.

To provide the barrel with a guiding function, the hole of the barrel is cylindrical. The sliding block includes two ends each having an end face. Each of the end faces of the sliding block has a curve corresponding to that of the inner periphery of the hole of the barrel. The pull cord extends through a center of the sliding block and is fixed to the sliding block.

To increase the sliding effect of the sleeve, the sleeve and the sliding block are made of plastic.

Compared to the current techniques, the present invention can effectively prevent the pull cord from tangling a child, providing use safety.

The present invention will become clearer in light of the following detailed description of illustrative embodiments of this invention described in connection with the drawings.

DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic view of a pull cord mechanism for a window shade according to the present invention.

FIG. 2 shows a cross sectional taken along section line A-A of FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

A pull cord mechanism for a window shade includes a frame 1, a shade 2, a shade driving mechanism 3, and a pull cord 4 for driving the shade driving mechanism 3. The shade driving mechanism 3 is fixed to the frame 1 and drives the shade 2 to fold and unfold. Particularly, a barrel 5 is mounted through a hook 6 to the frame 1 at a location corresponding to the pull cord 4. The barrel 5 includes a peripheral wall having a slit 7 extending in an axial direction. A sliding block 8 is slideably received in the barrel 5. A handle 9 is mounted to an outer periphery of the peripheral wall of the barrel 5. The sliding block 8 is connected to the handle 9 by a link 10 extending through the slit 7. The pull cord 4 is received in the barrel 5. The sliding block 8 is fixed to the pull cord 4 in the barrel 5. The shape of the cross sections 5 a of the barrel 5 is one of square, rectangular, circular, elliptic, polygonal, and plum blossom-shaped.

An end cap 11 is mounted to a tail end of the barrel 5.

The handle 9 is a sleeve having a hole 9 a. The hole 9 a has a shape of cross sections corresponding to that of the cross sections 5 a of the barrel 5.

The hole 5 b of the barrel 5 is cylindrical. The sliding block 8 includes two ends each having an end face 8 a. Each of the end faces 8 a of the sliding block 8 has a curve corresponding to that of the inner periphery of the hole 5 b of the barrel 5. The pull cord 4 extends through a center of the sliding block 8 and is fixed to the sliding block 8.

The sleeve 9 is made of plastic or aluminum alloy. The sliding block 8 is made of plastic or aluminum alloy. The sleeve 9, the sliding block 8, and the link 10 are integrally formed of plastic by injection molding or integrally formed by processing aluminum alloy. The barrel 5 is made of aluminum alloy or plastic.

Although specific embodiments have been illustrated and described, numerous modifications and variations are still possible without departing from the essence of the invention. The scope of the invention is limited by the accompanying claims. 

1. A pull cord mechanism for a window shade comprising a frame, a shade, a shade driving mechanism, and a pull cord for driving the shade driving mechanism, with the shade driving mechanism fixed to the frame, with the shade driving mechanism driving the shade to fold and unfold, the improvements comprising: a barrel mounted to the frame at a location corresponding to the pull cord, with the barrel including a peripheral wall having a slit extending in an axial direction, with a sliding block slideably received in the barrel, with a handle mounted to an outer periphery of the peripheral wall of the barrel, with the sliding block connected to the handle by a link extending through the slit, with the pull cord received in the barrel, with the sliding block fixed to the pull cord in the barrel.
 2. The pull cord mechanism for a window shade as claimed in claim 1, with the barrel having a tail end, with an end cap mounted to the tail end of the barrel.
 3. The pull cord mechanism for a window shade as claimed in claim 1, with the handle being a sleeve having a hole, with the hole having a shape of cross sections corresponding to that of cross sections of the barrel.
 4. The pull cord mechanism for a window shade as claimed in claim 3, with the shape of the cross sections of the barrel being one of square, rectangular, circular, elliptic, polygonal, and plum blossom-shaped.
 5. The pull cord mechanism for a window shade as claimed in claim 4, with the hole of the barrel being cylindrical, with the sliding block including two ends each having an end face, with each of the end faces of the sliding block having a curve corresponding to that of the inner periphery of the hole of the barrel.
 6. The pull cord mechanism for a window shade as claimed in claim 1, with the pull cord extending through a center of the sliding block and fixed to the sliding block.
 7. The pull cord mechanism for a window shade as claimed in claim 3, with the sleeve made of plastic or aluminum alloy, with the sliding block made of plastic or aluminum alloy, with the sleeve, the sliding block, and the link integrally formed of plastic by injection molding or integrally formed by processing aluminum alloy.
 8. The pull cord mechanism for a window shade as claimed in claim 7, with the barrel made of aluminum alloy or plastic. 